/*
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.l2j.gameserver.util;

import java.io.DataInputStream;
import java.io.File;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * This is a class loader for the dynamic extensions used by DynamicExtension class.
 * 
 * @version $Revision: $ $Date: $
 * @author  galun
 */
public class JarClassLoader extends ClassLoader
{
    private static final Logger _log = Logger.getLogger(JarClassLoader.class.getName());
    
    private Set<String> _jars = new HashSet<>();

    public void addJarFile(String filename)
    {
    	_jars.add(filename);
    }

    @Override
	public Class<?> findClass(String name) throws ClassNotFoundException
    {
    	try
    	{
    		byte[] b = loadClassData(name);
    		return defineClass(name, b, 0, b.length);
    	}
    	catch (Exception e)
    	{
    		throw new ClassNotFoundException(name);
    	}
    }

    private byte[] loadClassData(String name) throws IOException
    {
    	byte[] classData = null;
    	for (String jarFile : _jars)
        {
            File file = new File(jarFile);
            try (ZipFile zipFile = new ZipFile(file))
            {
	            String fileName = name.replace('.', '/') + ".class";
	            ZipEntry entry = zipFile.getEntry(fileName);
	            if (entry == null)
	                continue;
	
	            try (DataInputStream zipStream = new DataInputStream(zipFile.getInputStream(entry)))
	            {
	                classData = new byte[(int)entry.getSize()];
	                zipStream.readFully(classData, 0, (int) entry.getSize());
	                break;
	            }
	            catch (IOException e)
	            {
	                _log.log(Level.WARNING, jarFile + ":" + e.toString(), e);
	                continue;
	            }
            }
    	}

        if (classData == null)
            throw new IOException("class not found in " + _jars);
    	return classData;
    }
}